Massive 3G deployment greatly promotes use of data services. Facing fierce competition, in order to improve user loyalty, an operator provides QoS (Quality of Service) assurance for a data service as an important means.
PCC (Policy and Charging Control) is a set of policy and charging control mechanisms defined by the 3GPP (3rd Generation Partnership Project), and its architecture is shown in FIG. 1. The architecture includes a policy and charging enforcement function (PCEF), a traffic detection function (TDF), a bearer binding and event reporting function (BBERF), a policy and charging rules function (PCRF), an application function (AF), an online charging system (OCS), an offline charging system (OFCS), and a subscription profile repository (SPR). The architecture includes interfaces such as Gx, Sy, Gy, and Ro, where Gx is an interface between the PCRF and the PCEF, Sy is an interface between the PCRF and the OCS, Gy is an online charging interface between the PCEF and the OCS, and Ro is a collective term for online charging interfaces between a network element and the OCS. The PCEF is located in a gateway device, and the TDF is a logical function and may be disposed in or outside the gateway device.
The core of a PCC mechanism is as follows:
When establishing a data flow bearer, the gateway device requests, from the PCRF, a control policy and a charging policy for a data flow; according to subscription information stored in the SPR, information such as a user's accumulated usage or usage quota or account balance from the OCS (the accumulated usage, usage quota, account balance or the like from the OCS may be called counters), bearer layer information provided by the gateway device, and some local policies configured by an operator in the PCRF, the PCRF generates a policy on dynamic charging and service data flow control or determines a to-be-activated policy on static charging and service data flow control. Certainly, if the application function AF has provided the PCRF with service layer information of a service, the PCRF takes the service layer information into account when generating the policy on dynamic charging and service data flow control or determining the to-be-activated policy on static charging and service data flow control.
The PCRF delivers a command to the gateway device to install/activate the generated policy on dynamic charging and service data flow control or the policy on static charging and service data flow control, and the gateway device performs resource allocation, data flow control, and charging control according to the installed/activated policy; the PCEF may be triggered, according to the charging policy of the PCRF, to report a charging event and the user's usage information to the OCS; the OCS accumulates the user's usage information.
When the accumulation reaches a predefined threshold, the OCS reports accumulation information according to the user's Sy session between the PCRF and the OCS, so that the PCRF may further decide, based on the accumulation information, a data flow control policy, and deliver the decided policy to the PCEF for execution. The accumulation information is used to indicate a current accumulation status of a counter. The accumulation status indicates in which threshold range the counter is currently located. For example, when an accumulation amount of a counter is less than 100 MB, a status 1 is used as an indication; when the accumulation amount falls within 100 MB-1 GB, a status 2 is used as an indication; when the accumulation amount is greater than 1 GB, a status 3 is used as an indication. Subsequent counters and status definitions thereof are the same.
This mechanism can implement precise control on a service data flow according to an operator policy, so as to implement refined bandwidth operation.
When an existing technical solution is implemented, the following technical problems exist:
An existing Sy session is a user-level session, and a user of the Sy session and a user of a Gx session must be a same user, that is, users can use only their own accumulation information.
In an implementation process in which multiple users share a volume quota, this method requires a PCRF and a charging system to set an associated counter for each user, and requires the PCRF to subscribe to a same counter, namely, the associated counter, for each user in the charging system. The charging system needs to perform accumulation on the associated counter of each user no matter whether the user is online. Consequently, implementation is complicated in the PCRF and the charging system, and a quantity of signaling interactions between the PCRF and the charging system increases, which seriously affects the performance. Especially for a system that imposes a very high requirement of real-time performance, such as the OCS, the performance is significantly affected.